Isosorbide derivatives that can be used in detergent compositions for gasoline-type fuels

ABSTRACT

Compositions that comprise at least one compound that corresponds to the general formula in which R 1 , R 2 , R 3  and R 4  each represent a hydrogen atom or a  
                 
 
     hydrocarbon radical, for example alkyl, with 1 to 30 carbon atoms, whereby at least one of R 1 , R 2 , R 3  and R 4  is a hydrocarbon radical, m and m′ are each a number from 1 to 30, with m+m′ from 4 to 60, can be prepared by reaction of the isosorbide with one or more compounds that have an epoxide group. These compositions can be used as detergent additives for gasoline-type fuels.

[0001] The invention relates to new compounds that can be used by themselves or in mixtures in detergent additive compositions for fuels.

[0002] It is known that automobile engines have a tendency to form deposits on the surface of the engine elements, in particular on the carburetor orifices, the bodies of butterfly valves, fuel injectors, cylinder orifices and intake valves, because of oxidation and polymerization of various hydrocarbon-containing components of the fuel. These deposits, even when they are present only in small amounts, are often responsible for significant driving problems, such as the engine timing and poor acceleration. In addition, deposits on the engine can significantly increase the consumption of fuel and the production of pollutants. This is why the development of effective detergent additives for regulating these deposits assumes a considerable importance and was already the object of much research.

[0003] A new family of compounds that exhibit good effectiveness as additives that are intended to reduce the deposits on the injectors and on the intake valves has now been discovered.

[0004] The compounds of the invention can be defined by the following general formula (I):

[0005] in which R₁, R₂, R₃, and R₄ each represent a hydrogen atom or a hydrocarbon radical, for example alkyl, with 1 to 30 carbon atoms, whereby at least one of R₁, R₂, R₃, and R₄ is a hydrocarbon radical; m and m′ are each a number from 1 to 30, preferably 1 to 20, with m+m′ from 4 to 60, preferably 5 to 30.

[0006] In the same formula (I), the concatenations

[0007] can respectively consist of patterns:

[0008] that differ from one another by the nature of R₁, R₂, R₃ and/or R₄.

[0009] The compounds of the invention generally come in the form of mixtures of compounds that differ from one another by the value of m and/or m′ and/or by the nature of radicals R₁, R₂, R₃ and R₄. Rather than compounds, it is then a matter of compositions.

[0010] The synthesis of the compounds or compositions defined above can be carried out as described below.

[0011] The isosorbide of formula:

[0012] is reacted with one or more compounds that have an epoxide group, with general formula:

[0013] in which R₁, R₂, R₃, and R₄ each represent a hydrogen atom or a hydrocarbon radical, for example alkyl with 1 to 30 carbon atoms, whereby at least one of R₁, R₂, R₃ and R₄ is a hydrocarbon radical.

[0014] The stages of the preparation are generally as follows:

[0015] a) In a first step, the isosorbide is transformed into an alkaline metal alcoholate (for example sodium or potassium), by reaction with an alkaline hydroxide (for example soda or potash), an alkaline hydride or any other compound that can form an alcoholate with the isosorbide;

[0016] b) in a second step, the alkaline alcoholate triggers the polymerization of the epoxide(s) by opening its (their) rings; and

[0017] c) in a third step, the alcoholate-termination polyether that is formed is treated by water, an acid or any other compound with mobile hydrogen, in order to transform the alcoholate terminations into alcohol groups.

[0018] Described below, by way of illustration, is a special operating procedure, whereby it is understood that the preparation of the compounds and compositions of the invention can be carried out by any other equivalent method.

[0019] The isosorbide is mixed with, for example, sodium hydride (at a rate of, for example, about 0.5% by weight). After having purged, under stirring, the reactor of the released hydrogen, an epoxide or an epoxide mixture is introduced in an amount that is calculated to obtain the desired value of m+m′ at a temperature of 80 to 180° C., and the reaction mixture is kept at this temperature until the consumption of the epoxide(s) is finished. After returning to ambient temperature, the medium is diluted with an organic solvent, for example a hydrocarbon solvent, such as heptane, it is washed with water one or more times, then, after evaporation under reduced pressure of the organic phase, the desired product that corresponds to general formula (I):

[0020] is obtained.

[0021] The compositions of the invention can be used as detergent additives in the gasoline-type fuels. In this application, they can be added to the fuels at concentrations of, for example, 20 to 5000 mg/liter. They can also be used mixed with any other detergent compound.

[0022] The following examples illustrate the invention without limiting its scope.

EXAMPLE 1

[0023] In a reactor that makes it possible to operate under pressure, equipped with a stirring system, a system for introducing reagents, a system for measuring temperature and pressure, 43.8 g (0.3 mol) of isosorbide and 0.3 g of sodium hydride are introduced. After having purged, under stirring, the reactor of the released hydrogen, 300 g (4.16 mol) of 1,2-epoxybutane is introduced. The medium is gradually brought to the temperature of 145° C., and it is kept at this temperature until the drop in pressure indicates the consumption of 1,2-epoxybutane is finished. After returning to ambient temperature, the medium is diluted with heptane, washed with 2×100 g of water, then, after evaporation under reduced pressure of the organic phase, 337 g of a clear pale yellow liquid is obtained that is soluble in gasoline and whose structure corresponds to the general formula:

[0024] in which R₁=R₂=R₃=H; R₄=—CH₂—CH₃; and (m+m′)_(mean)=14.

EXAMPLE 2

[0025] In a reactor that makes it possible to operate under pressure, equipped with a stirring system, a system for introducing reagents, and a system for measuring temperature and pressure, 43.8 g of isosorbide (0.3 mol) and 0.3 g of sodium hydride are introduced. After having purged, under stirring, the reactor of the released hydrogen, 420 g (5.8 mol) of 1,2-epoxybutane is introduced. The medium is gradually brought to the temperature of 145° C., and it is kept at this temperature until the drop in pressure indicates the consumption of 1,2-epoxybutane is finished. After returning to ambient temperature, the medium is diluted with heptane, washed with 2×100 g of water, then, after evaporation under reduced pressure of the organic phase, 453 g of a clear pale yellow liquid is obtained that is soluble in gasoline and whose structure corresponds to the general formula:

[0026] in which R₁=R₂=R₃=H; R₄=—CH₂—CH₃; and (m+m′)_(mean)=19.

EXAMPLE 3

[0027] In a reactor that makes it possible to operate under pressure, equipped with a stirring system, a system for introducing reagents, a system for measuring temperature and pressure, 43.8 g of isosorbide (0.3 mol) and 0.3 g of sodium hydride are introduced. After having purged, under stirring, the reactor of the released hydrogen, 300 g (5.2 mol) of 1,2-epoxypropane is introduced. The medium is gradually brought to the temperature of 145° C., and it is kept at this temperature until the drop in pressure indicates that the consumption of 1,2-epoxypropane is finished. After returning to ambient temperature, the medium is diluted with heptane, washed with 2×100 g of water, then, after evaporation under reduced pressure of the organic phase, 335 g of a clear pale yellow liquid is obtained that is soluble in gasoline and whose structure corresponds to the general formula:

[0028] in which R₁=R₂=R₃=H; R₄=—CH₃; and (m+m′)_(mean)=17.

EXAMPLE 4

[0029] In a reactor that makes it possible to operate under pressure, equipped with a stirring system, a system for introducing reagents, a system for measuring temperature and pressure, 43.8 g of isosorbide (0.3 mol) and 0.3 g of sodium hydride are introduced. After having purged, under stirring, the reactor of the released hydrogen, 210 g (2.9 mol) of 1,2-epoxybutane and 90 g of 1,2 epoxydodecane (0.48 mol) are introduced. The medium is gradually brought to the temperature of 145° C., and it is kept at this temperature for five hours. After returning to ambient temperature, the medium is diluted with heptane, washed with 2×100 g of water, then, after evaporation under reduced pressure of the organic phase, 333 g of a clear pale yellow liquid is obtained that is soluble in gasoline and whose structure corresponds to the general formula:

[0030] in which R₁=R₂=R₃=H; R₄=—CH₂—CH₃ or —(CH₂)₉—CH₃; and (m+m′)_(mean)=14.6.

EXAMPLE 5

[0031] The products that are prepared in preceding examples 1 and 4 are evaluated as additives for their detergent properties at a concentration of 400 mg/liter in an unleaded gasoline with a “research” octane number of 96.8 and whose characteristics appear in Table 1 below. TABLE 1 Density at 15° C. 753.9 kg/m3  Reid vapor pressure 60.2 kPa  Lead content < 2 mg/1 Distillation Starting point  33.0° C.  5%  45.9° C. 10%  51.2° C. 20%  61.1° C. 30%  73.1° C. 40%  88.3° C. 50% 104.2° C. 60% 116.0° C. 70% 125.6° C. 80% 138.5° C. 90% 155.6° C. 95% 169.8° C. End point 189.0° C.

[0032] The evaluation is carried out with a test on a Mercedes M102E engine according to the CEC-F-05-A-93 method. The duration of this test is 60 hours. This method makes it possible to evaluate the amount of deposits that are formed on the intake valves of the engine.

[0033] The results that appear in Table 2 show the effect of the products of the invention for reducing the deposits on the intake valves. TABLE 2 Content Deposited Material on the Intake Valves (mg) Additive (mg/l) Valve 1 Valve 2 Valve 3 Valve 4 Mean None  0 241 275 272 312 275   Product of 400  54  31  33  55 43   Example 1 Product of 400  13  16  17  4 12.5 Example 4 

1. Compound characterized in that it corresponds to general formula (I):

in which R₁, R₂, R₃, and R₄ each represent a hydrogen atom or a hydrocarbon radical, whereby at least one of R₁, R₂, R₃, and R₄ is a hydrocarbon radical; and m and m′ are each a number from 1 to 30, with m+m′ from 4 to
 60. 2. Compound according to claim 1, wherein in general formula (I), the concatenations:

consist respectively of patterns:

that differ from one another by the nature of R₁, R₂, R₃ and/or R₄.
 3. Compound according to claim 1 or 2, wherein in formula (I), m and m′ are each a number from 1 to 20, with m+m′ from 5 to
 30. 4. Compound according to one of claims 1 to 3, wherein in general formula (I), hydrocarbon radicals R₁, R₂, R₃ and R₄ are alkyl radicals with 1 to 30 carbon atoms.
 5. Composition, wherein it consists of a mixture of at least two compounds according to one of claims 1 to 4 that differ from one another by the values of m and/or m′ and/or by the nature of at least one of radicals R₁ to R₄.
 6. Process for preparation of a compound according to one of claims 1 to 4 or a composition according to claim 5, wherein the isosorbide of the formula:

is reacted with one or more compounds that have an epoxide group and that correspond to the general formula:

in which R₁, R₂, R₃, and R₄ are defined as in one of claims 1 to
 4. 7. Process according to claim 6, wherein a) In a first step, the isosorbide is transformed into an alkaline metal alcoholate by reaction with an alkaline hydroxide, an alkaline hydride or any other compound that can form an alcoholate with the isosorbide; b) in a second step, the alkaline alcoholate triggers the polymerization of the epoxide(s) by opening its (their) rings; c) in a third step, the alcoholate-termination polyether that is formed is treated by water, an acid or any other compound with mobile hydrogen, in order to transform the alcoholate terminations into alcohol groups.
 8. Process according to claim 6 or 7, wherein the isosorbide is mixed with sodium hydride; the reactor is purged, under stirring, of the released hydrogen; the epoxide or an epoxide mixture is introduced in an amount that is calculated to obtain the desired value of m+m′ at a temperature of 80 to 180° C.; and the reaction mixture is kept at this temperature until the consumption of the epoxide(s) is finished; after returning to ambient temperature, the medium is diluted with an organic solvent; it is washed with water one or more times, then, after evaporation under reduced pressure of the organic phase, a compound according to one of claims 1 to 4 or a composition according to claim 5 is obtained.
 9. Use of a compound according to one of claims 1 to 4 or a composition according to claim 5 as a detergent additive in a gasoline.
 10. Use according to claim 9, wherein said compound or said composition is used in a mixture with any other detergent compound. 